Figure 20.16 Effects of growth rate on stoichiometry. (a) Slow-growing organisms, such as this marine copepod, have tissues with a high ratio of nitrogen to phosphorus of approximately 50:1. (b) fast-growing organisms, such as this water flea (Daphnia magna), require much more phosphorus so that they can produce nucleic acids. As a result, their tissues have a lower ratio of nitrogen to phosphorus that is approximately 15:1.

Photos by (a) Image Quest Marine and (b) Laguna Design/Science Source.